535 5.7.0 (#AUTH005) Too many bad auth attempts error when trying to send email.

If you receive this error, most likely you are using Yahoo for the email server or an email server managed by Yahoo, such as AOL or AT&T. Yahoo has implemented an option that by default, does not let 3rd party products access the email servers.  

To resolve, go to https://login.yahoo.com/account/security and then enable the option to allow apps that use less secure sign in.  If you are using AOL, do the same thing, from https://login.aol.com/account/security